Óleos comestíveis extraídos mecanicamente de frutos da palmeira Acrocomia aculeata como novos alimentos: processamento, caracterização e cinética de degradação térmica de compostos bioativos

Abstract

This doctoral thesis was developed with the general objective of assessing processing effects and conditions in the quality parameters of vegetable oils mechanically extracted from fresh Acrocomia aculeata fruit, for human consumption as a novel food. In this sense, this work hascontributed with the first report on the assessment of different extractions conditions to mechanically obtain high-quality macauba oil for multi-purpose employments, including food processing. The coldly pressed (34 °C) virgin edible oil (mesocarp oil), which showed the highest tocols (tocopherol and tocotrienols) content (85.5 mg.kg-1), the higher oil stability index (6.4 hours) and a low acid value (1.6 mg KOH g-1) was comprehensive characterized in terms of quality, composition and identity parameters (i.e., peroxide value, insoluble impurities, mineralcontents, fatty acids essential composition, iodine value, saponification value, kinematic viscosity, relative density, unsaponifiable matter and total carotenoids). Results were compared with literature sources to develop a baseline of information concerning the raw material, reinforcing the novelty of this study. The nutraceutical potential of A. aculeata was highlighted, strengthening the existing scientific evidence. Kinetic modelling involving the thermal degradation of carotenoids was performed in the macauba oil to assess food processing effectsquantitatively. The results obtained between 373.15 K and 423.15 K indicated that the first order kinetic model is appropriate for describing the oxidative degradation of overall carotenoids (Ea: 84 kJ.mol-1; kref: 1.1 x 10-3 min-1), as well as of individual -carotene (Ea: 80 kJ.mol-1; kref: 1.2 x 10-3 min-1) and -cryptoxanthin (Ea: 87 kJ.mol-1; kref: 1.0 x 10-3 min-1), in the macauba oil. As kinetic data is also used in engineering design, this study filled a research gap on A. aculeata, gaining further insight into the reactivity of carotenoids and the macauba productive chain. Thepotential of jointly utilising fresh oils from macauba mesocarp and kernel was presented, for different blends of vegetable oils be attained, as a way of enhancing the nutritional characteristics of structural lipids with functional properties. Kinetic predictions were thereby carried out formaking it feasible to evaluate possible thermal effects on the carotenoids retention in the oil studied (393.15 K; 120 min) which may result from interesterification processing conditions. The research timely took into account computational capabilities that have either emerged the use ofspecific kinetic data and procedures to understand thermal processing as an essential unity operation on food context. Overall, the doctoral thesis has assessed the processing effects and conditions, integrating results and knowledge regarding one of the highest oil-yielding plants inthe world, improving the prospects of Acrocomia aculeata as an alternative source of high-quality raw material, for multi-purpose employments, including for producing novel food